This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 23 |
| 4 | 117 |
| 5 | 636 |
| 6 | 3607 |
| 7 | 21106 |
| 8 | 126489 |
| 9 | 772468 |
| 10 | 4789844 |
| 11 | 30075937 |
| 12 | 190851839 |
| 13 | 1222000222 |
| 14 | 7885041530 |
| 15 | 51222338580 |
| 16 | 334720178969 |
| 17 | 2198755865424 |
| 18 | 14511029102232 |
| 19 | 96169424666028 |
| 20 | 639757737711300 |
| 21 | 4270520564506069 |
| 22 | 28595671605541357 |
| 23 | 192025292117465445 |
| 24 | 1292866976587651519 |